This invention relates to communication between a processor and various satellite processors. More particularly, it relates to communication between a service processor and a satellite programmable devices which monitor various aspects of a data processing system.
In today's increasingly complex electronic data processing systems, more and more use is being made of simple programmable devices scattered throughout the system to monitor various aspects of the system and its environment. These satellite devices form part of the means through which a portion of the system, typically a service processor, can keep track of system parameters and, to some extent, modify them.
Among the parameters monitored by these satellite devices are several (e.g., temperature, voltage, current) which, if they exceed certain boundary conditions, can severely damage the system. When such conditions are identified, immediate corrective action is absolutely essential.
One impediment to immediate action is the fact that the conditions are normally arranged in groups for presentation to the service processor. For example, an over-temperature condition in one portion of a data processing system will typically result in a signal to the service processor which tells it only that one problem within a certain class of problems has arisen. In the typical prior art system, the service processor would then need to interrogate various units to determine the precise problem. In some situations, this interrogation could take enough time for substantial system damage to occur. For this reason, it is quite common in data processing systems for certain problems, such as over-temperature conditions, to be resolved by immediately shutting down a portion or all of the system.
Another approach to a solution of this problem is to increase the capability of the satellite units which monitor the system. If these units are made powerful enough to deal with the problem entirely on their own, rather than have to communicate with a service processor, then the problems involved in the time required for such communication will be obviated. However, this type of solution will increase the cost and completely of the data processing system.